Mood disorders (MD) affect nearly 15% of youth and are severely debilitating. Mood impairments are often expressed through difficulties with adaptive emotion regulation that present clinically as persistent hyper- or hypo-reactivity of emotions (i.e., increased elation, irritability or anhedonia), and excessive approach or avoidance behaviors, resulting in significant psychosocial difficulties. Consistent with strategies set forthby the NIMH Research Domain Criteria, this project aims to characterize symptoms ...based on dimensions of observable behaviors and brain functions with a particular focus on biomarkers and behaviors associated with the positive and negative valence systems, such as approach motivation and response to reward/non-reward. This proposal aims to use neurophysiological markers (electroencephalography [EEG] and event-related potentials [ERPs]) of approach motivation and reward/non-reward sensitivity, as well as behavioral response (distress tolerance), to predict mood stability in 60 youth with MD. Identifying markers of symptom maintenance will elucidate intervention targets and aid in treatment selection. The study involves a single laboratory assessment and two symptom follow-up assessments at 3- and 6-months. This proposal provides the optimal training for the applicant to gain expertise in EEG methods and analysis needed to conduct independent, patient-oriented, neurodevelopmental research on neural mechanisms associated with approach motivation and reward sensitivity.